/*
 * Copyright (C)2005-2019 Haxe Foundation
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 */

package haxe;

import haxe.ds.List;

/**
	The Serializer class can be used to encode values and objects into a `String`,
	from which the `Unserializer` class can recreate the original representation.

	This class can be used in two ways:

	- create a `new Serializer()` instance, call its `serialize()` method with
		any argument and finally retrieve the String representation from
		`toString()`
	- call `Serializer.run()` to obtain the serialized representation of a
		single argument

	Serialization is guaranteed to work for all haxe-defined classes, but may
	or may not work for instances of external/native classes.

	The specification of the serialization format can be found here:
	<https://haxe.org/manual/std-serialization-format.html>
**/
class Serializer {
	/**
		If the values you are serializing can contain circular references or
		objects repetitions, you should set `USE_CACHE` to true to prevent
		infinite loops.

		This may also reduce the size of serialization Strings at the expense of
		performance.

		This value can be changed for individual instances of `Serializer` by
		setting their `useCache` field.
	**/
	public static var USE_CACHE = false;

	/**
		Use constructor indexes for enums instead of names.

		This may reduce the size of serialization Strings, but makes them less
		suited for long-term storage: If constructors are removed or added from
		the enum, the indices may no longer match.

		This value can be changed for individual instances of `Serializer` by
		setting their `useEnumIndex` field.
	**/
	public static var USE_ENUM_INDEX = false;

	static var BASE64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789%:";
	static var BASE64_CODES = null;

	var buf:StringBuf;
	var cache:Array<Dynamic>;
	var shash:haxe.ds.StringMap<Int>;
	var scount:Int;

	/**
		The individual cache setting for `this` Serializer instance.

		See `USE_CACHE` for a complete description.
	**/
	public var useCache:Bool;

	/**
		The individual enum index setting for `this` Serializer instance.

		See `USE_ENUM_INDEX` for a complete description.
	**/
	public var useEnumIndex:Bool;

	/**
		Creates a new Serializer instance.

		Subsequent calls to `this.serialize` will append values to the
		internal buffer of this String. Once complete, the contents can be
		retrieved through a call to `this.toString`.

		Each `Serializer` instance maintains its own cache if `this.useCache` is
		`true`.
	**/
	public function new() {
		buf = new StringBuf();
		cache = new Array();
		useCache = USE_CACHE;
		useEnumIndex = USE_ENUM_INDEX;
		shash = new haxe.ds.StringMap();
		scount = 0;
	}

	/**
		Return the String representation of `this` Serializer.

		The exact format specification can be found here:
		https://haxe.org/manual/serialization/format
	**/
	public function toString() {
		return buf.toString();
	}

	/* prefixes :
		a : array
		b : hash
		c : class
		d : Float
		e : reserved (float exp)
		f : false
		g : object end
		h : array/list/hash end
		i : Int
		j : enum (by index)
		k : NaN
		l : list
		m : -Inf
		n : null
		o : object
		p : +Inf
		q : haxe.ds.IntMap
		r : reference
		s : bytes (base64)
		t : true
		u : array nulls
		v : date
		w : enum
		x : exception
		y : urlencoded string
		z : zero
		A : Class<Dynamic>
		B : Enum<Dynamic>
		M : haxe.ds.ObjectMap
		C : custom
	 */
	function serializeString(s:String) {
		var x = shash.get(s);
		if (x != null) {
			buf.add("R");
			buf.add(x);
			return;
		}
		shash.set(s, scount++);
		#if old_serialize
		// no more support for -D old_serialize due to 'j' reuse
		#if error
		#end
		#end
		buf.add("y");
		s = StringTools.urlEncode(s);
		buf.add(s.length);
		buf.add(":");
		buf.add(s);
	}

	function serializeRef(v:Dynamic) {
		#if js
		var vt = js.Syntax.typeof(v);
		#end
		for (i in 0...cache.length) {
			#if js
			var ci = cache[i];
			if (js.Syntax.typeof(ci) == vt && ci == v) {
			#else
			if (cache[i] == v) {
			#end
				buf.add("r");
				buf.add(i);
				return true;
			}
		}
		cache.push(v);
		return false;
	}

	#if flash
	// only the instance variables

	function serializeClassFields(v:Dynamic, c:Dynamic) {
		var xml:flash.xml.XML = untyped __global__["flash.utils.describeType"](c);
		var vars = xml.factory[0].child("variable");
		for (i in 0...vars.length()) {
			var f = vars[i].attribute("name").toString();
			if (!v.hasOwnProperty(f))
				continue;
			serializeString(f);
			serialize(Reflect.field(v, f));
		}
		buf.add("g");
	}
	#end

	function serializeFields(v:{}) {
		for (f in Reflect.fields(v)) {
			serializeString(f);
			serialize(Reflect.field(v, f));
		}
		buf.add("g");
	}

	/**
	Serializes `v`.

	All haxe-defined values and objects with the exception of functions can
	be serialized. Serialization of external/native objects is not
	guaranteed to work.

	The values of `this.useCache` and `this.useEnumIndex` may affect
	serialization output.
**/
	public function serialize(v:Dynamic) {
		switch (Type.typeof(v)) {
			case TNull:
				buf.add("n");
			case TInt:
				var v:Int = v;
				if (v == 0) {
					buf.add("z");
					return;
				}
				buf.add("i");
				buf.add(v);
			case TFloat:
				var v:Float = v;
				if (Math.isNaN(v))
					buf.add("k");
				else if (!Math.isFinite(v))
					buf.add(if (v < 0) "m" else "p");
				else {
					buf.add("d");
					buf.add(v);
				}
			case TBool:
				buf.add(if (v) "t" else "f");
			case TClass(c):
				if (#if neko untyped c.__is_String #else c == String #end) {
					serializeString(v);
					return;
				}
				if (useCache && serializeRef(v))
					return;
				switch (#if (neko || cs || python) Type.getClassName(c) #else c #end) {
					case #if (neko || cs || python) "Array" #else cast Array #end:
						var ucount = 0;
						buf.add("a");
						#if (flash || python || hl)
						var v:Array<Dynamic> = v;
						#end
						var l = #if (neko || flash || php || cs || java || python || hl || lua || eval) v.length #elseif cpp v.__length() #else __getField(v,
							"length") #end;
						for (i in 0...l) {
							if (v[i] == null)
								ucount++;
							else {
								if (ucount > 0) {
									if (ucount == 1)
										buf.add("n");
									else {
										buf.add("u");
										buf.add(ucount);
									}
									ucount = 0;
								}
								serialize(v[i]);
							}
						}
						if (ucount > 0) {
							if (ucount == 1)
								buf.add("n");
							else {
								buf.add("u");
								buf.add(ucount);
							}
						}
						buf.add("h");
					case #if (neko || cs || python) "haxe.ds.List" #else cast List #end:
						buf.add("l");
						var v:List<Dynamic> = v;
						for (i in v)
							serialize(i);
						buf.add("h");
					case #if (neko || cs || python) "Date" #else cast Date #end:
						var d:Date = v;
						buf.add("v");
						buf.add(d.getTime());
					case #if (neko || cs || python) "haxe.ds.StringMap" #else cast haxe.ds.StringMap #end:
						buf.add("b");
						var v:haxe.ds.StringMap<Dynamic> = v;
						for (k in v.keys()) {
							serializeString(k);
							serialize(v.get(k));
						}
						buf.add("h");
					case #if (neko || cs || python) "haxe.ds.IntMap" #else cast haxe.ds.IntMap #end:
						buf.add("q");
						var v:haxe.ds.IntMap<Dynamic> = v;
						for (k in v.keys()) {
							buf.add(":");
							buf.add(k);
							serialize(v.get(k));
						}
						buf.add("h");
					case #if (neko || cs || python) "haxe.ds.ObjectMap" #else cast haxe.ds.ObjectMap #end:
						buf.add("M");
						var v:haxe.ds.ObjectMap<Dynamic, Dynamic> = v;
						for (k in v.keys()) {
							#if (js || neko)
							var id = Reflect.field(k, "__id__");
							Reflect.deleteField(k, "__id__");
							serialize(k);
							Reflect.setField(k, "__id__", id);
							#else
							serialize(k);
							#end
							serialize(v.get(k));
						}
						buf.add("h");
					case #if (neko || cs || python) "haxe.io.Bytes" #else cast haxe.io.Bytes #end:
						var v:haxe.io.Bytes = v;
						#if neko
						var chars = new String(base_encode(v.getData(), untyped BASE64.__s));
						buf.add("s");
						buf.add(chars.length);
						buf.add(":");
						buf.add(chars);
						#else
						buf.add("s");
						buf.add(Math.ceil((v.length * 8) / 6));
						buf.add(":");

						var i = 0;
						var max = v.length - 2;
						var b64 = BASE64_CODES;
						if (b64 == null) {
							b64 = new haxe.ds.Vector(BASE64.length);
							for (i in 0...BASE64.length)
								b64[i] = BASE64.charCodeAt(i);
							BASE64_CODES = b64;
						}
						while (i < max) {
							var b1 = v.get(i++);
							var b2 = v.get(i++);
							var b3 = v.get(i++);

							buf.addChar(b64[b1 >> 2]);
							buf.addChar(b64[((b1 << 4) | (b2 >> 4)) & 63]);
							buf.addChar(b64[((b2 << 2) | (b3 >> 6)) & 63]);
							buf.addChar(b64[b3 & 63]);
						}
						if (i == max) {
							var b1 = v.get(i++);
							var b2 = v.get(i++);
							buf.addChar(b64[b1 >> 2]);
							buf.addChar(b64[((b1 << 4) | (b2 >> 4)) & 63]);
							buf.addChar(b64[(b2 << 2) & 63]);
						} else if (i == max + 1) {
							var b1 = v.get(i++);
							buf.addChar(b64[b1 >> 2]);
							buf.addChar(b64[(b1 << 4) & 63]);
						}
						#end
					default:
						if (useCache) cache.pop();
						if (#if flash try
							v.hxSerialize != null
						catch (e:Dynamic)
							false #elseif (cs || java || python) Reflect.hasField(v,
								"hxSerialize") #elseif php php.Global.method_exists(v, 'hxSerialize') #else v.hxSerialize != null #end) {
							buf.add("C");
							serializeString(Type.getClassName(c));
							if (useCache)
								cache.push(v);
							v.hxSerialize(this);
							buf.add("g");
						} else {
							buf.add("c");
							serializeString(Type.getClassName(c));
							if (useCache)
								cache.push(v);
							#if flash
							serializeClassFields(v, c);
							#else
							serializeFields(v);
							#end
						}
				}
			case TObject:
				if (Std.is(v, Class)) {
					var className = Type.getClassName(v);
					#if (flash || cpp)
					// Currently, Enum and Class are the same for flash and cpp.
					//  use resolveEnum to test if it is actually an enum
					if (Type.resolveEnum(className) != null)
						buf.add("B")
					else
					#end
					buf.add("A");
					serializeString(className);
				} else if (Std.is(v, Enum)) {
					buf.add("B");
					serializeString(Type.getEnumName(v));
				} else {
					if (useCache && serializeRef(v))
						return;
					buf.add("o");
					serializeFields(v);
				}
			case TEnum(e):
				if (useCache) {
					if (serializeRef(v))
						return;
					cache.pop();
				}
				buf.add(useEnumIndex ? "j" : "w");
				serializeString(Type.getEnumName(e));
				#if neko
				if (useEnumIndex) {
					buf.add(":");
					buf.add(v.index);
				} else
					serializeString(new String(v.tag));
				buf.add(":");
				if (v.args == null)
					buf.add(0);
				else {
					var l:Int = untyped __dollar__asize(v.args);
					buf.add(l);
					for (i in 0...l)
						serialize(v.args[i]);
				}
				#elseif flash
				if (useEnumIndex) {
					buf.add(":");
					var i:Int = v.index;
					buf.add(i);
				} else
					serializeString(v.tag);
				buf.add(":");
				var pl:Array<Dynamic> = v.params;
				if (pl == null)
					buf.add(0);
				else {
					buf.add(pl.length);
					for (p in pl)
						serialize(p);
				}
				#elseif cpp
				var enumBase:cpp.EnumBase = v;
				if (useEnumIndex) {
					buf.add(":");
					buf.add(enumBase.getIndex());
				} else
					serializeString(enumBase.getTag());
				buf.add(":");
				var len = enumBase.getParamCount();
				buf.add(len);
				for (p in 0...len)
					serialize(enumBase.getParamI(p));
				#elseif php
				if (useEnumIndex) {
					buf.add(":");
					buf.add(v.index);
				} else
					serializeString(v.tag);
				buf.add(":");
				var l:Int = php.Syntax.code("count({0})", v.params);
				if (l == 0 || v.params == null)
					buf.add(0);
				else {
					buf.add(l);
					for (i in 0...l) {
						#if php
						serialize(v.params[i]);
						#end
					}
				}
				#elseif (java || cs || python || hl || eval)
				if (useEnumIndex) {
					buf.add(":");
					buf.add(Type.enumIndex(v));
				} else
					serializeString(Type.enumConstructor(v));
				buf.add(":");
				var arr:Array<Dynamic> = Type.enumParameters(v);
				if (arr != null) {
					buf.add(arr.length);
					for (v in arr)
						serialize(v);
				} else {
					buf.add("0");
				}
				#elseif (js && !js_enums_as_arrays)
				if (useEnumIndex) {
					buf.add(":");
					buf.add(v._hx_index);
				} else
					serializeString(Type.enumConstructor(v));
				buf.add(":");
				var params = Type.enumParameters(v);
				buf.add(params.length);
				for (p in params)
					serialize(p);
				#else
				if (useEnumIndex) {
					buf.add(":");
					buf.add(v[1]);
				} else
					serializeString(v[0]);
				buf.add(":");
				var l = __getField(v, "length");
				buf.add(l - 2);
				for (i in 2...l)
					serialize(v[i]);
				#end
				if (useCache)
					cache.push(v);
			case TFunction:
				throw "Cannot serialize function";
			default:
				#if neko
				if (untyped (__i32__kind != null && __dollar__iskind(v, __i32__kind))) {
					buf.add("i");
					buf.add(v);
					return;
				}
				#end
				throw "Cannot serialize " + Std.string(v);
		}
	}

	extern inline function __getField(o:Dynamic, f:String):Dynamic
		return o[cast f];

	public function serializeException(e:Dynamic) {
		buf.add("x");
		#if flash
		if (untyped __is__(e, __global__["Error"])) {
			var e:flash.errors.Error = e;
			var s = e.getStackTrace();
			if (s == null)
				serialize(e.message);
			else
				serialize(s);
			return;
		}
		#end
		serialize(e);
	}

	/**
	Serializes `v` and returns the String representation.

	This is a convenience function for creating a new instance of
	Serializer, serialize `v` into it and obtain the result through a call
	to `toString()`.
**/
	public static function run(v:Dynamic) {
		var s = new Serializer();
		s.serialize(v);
		return s.toString();
	}

	#if neko
	static var base_encode = neko.Lib.load("std", "base_encode", 2);
	#end
}
